Process of and means for making rotary pistons with stepped windings for use in connection with rotary piston engines



Feb. 6, 1934, MQC EMBA 1,946,410 PROCESS OF AND MEANS FOR MAKING ROT PISTONS WITH STEPPED WINDINGS FOR USE IN co CTION WITH ROTARY PISTON ENGINES led March 6. 1930 V INVeNTOFfi Patented Feb. 6, 1934 UNITED STATES v 1,94a4l1t PATENT 'o-FFICE INGS FOR USE IN CONNECTION WITH ROTARY PISTON ENGINES Emanuel Mocigemba, Essen, Germany, .assignor to Aktiengesellschaft fur Liechtenstein,

Montanbe'darf, Vaduz,

a company of Liechtenstein Application March 6, 1930, Serial No. 433,757, and in Austria March 8, 1929 6 Claims. (01. 90-15) which corresponds to the diameter of the body portion of the piston-member, is provided with slots extending at a right angle with respect to the axis of the cylindric member and down to the inner wall of the latter, said slots being displaced with respect to one another on the periphery as well as in the axial direction, whereby a continuous member is produced which forms the piston windings. The invention further relates to a particular mode of cutting in order to produce pistons of a certain kind.

The invention is illustrated by way of example on the accompanying sheet of drawings in which:-- 7

Figures 1-4 of the drawing show diagrammatically a device for carrying out the method.

Figure 1 is a plan view of the gripped piston bodies.

Figure 2 is a side elevation with the feed mechanism for turning the cylindrical members.

Figures 3 and 4 are front elevation and plan views, respectively, on a smaller scale showing the arrangement of the cutters.

Figures 5, 6 and 7 show developments of different constructional forms of rotary pistons produced by a special cutting method.

Figure 1 shows the gripping arrangement of the four cylindrical pistons which are cut through in one operation. Two pistons are cut during each gripping operation. The cylindrical bodies are inserted with one end in bearings 1 and the cylindrical pistons are secured by means of conical collars or sleeves 2. The cones are tightened by the spindles 3 by means of the nuts 4.

After the cutting operation, the cylindrical -.bodies are always relatively rotated in pairs through a certain angle which is effected by the worm wheels 5 and the worms 6. The spindle 8, on which the two left-handed and. the two righthanded worms 6 are mounted, is rotated by a handle on the square member '7 until the worm "wheels 5 are rotated in pairs through the desired angle. A new cut is now made by means of the cutter 9 which is secured to the cutter spindle 10 of the milling machine 11. I 7 automatic movementof the longitudinal support 12 through the milling machine, the cutter 9 mounted on the cross support or slide 12 and 13 is moved rectangular to the axis of the pistons so that a cutting slot is formed. After the formation of the cutting slot, the cross support or slide 131s moved by meansof the toothed wheels 15 of the spindle 16 and nutl'? by means of a handle adapted to turn on the square member 18. By a correct selection of the toothed wheels 15 in accordance with the pitch of the spindle 16 the cutting width can be adjusted in an accurate and simple manner and fixed by means of a dividing plate,

In operation, the milling machine according to the present invention differs from milling machines of other constructions in that the, axis of rotation of the cutter is disposed parallel with respect of the axis round which, the workpiece is rotated stepwiseand during the cutting operation the cutter is fed forward in a direction which vertically transects the axis of the workpiece, the latter being fed forward between two cuttings in a direction, which is parallel with respect to the axis of rotation of the workpiece.

As described hereinafter, the shape of 1 the windings in the pistons depends on the extent of rotation of the cylinders as well as, on the extent of the feed of the cutter. Both cylinders areprovided with exactly fitting counter shapes in view of the method of positively rotating in opposite directions and cutting by the same tool ina single operation two members which are intended to operate together. The front faces, 19 are subsequently shaped in such a manner that their shape corresponds to the flank of the tooth. Hereafter the ribs are pushed onto and fitted to the oylindric body portion and fixed by setscrews or the like.

Fig. 5 illustrates the development of a pistonbody of known construction. Thispiston-body is produced according to the known method in that thecutter, the width of which corresponds to the width b of the ribs and slots, is axially shifted for the extent of the width b after each cutting operation, while the workpiece is rotated over half the circumference less the distance d after each cutting operation. The chambers of piston-bodies of this kind, through which the operating medium successively flows, are displaced for their whole width and therefore the operating medium is deflected at a right angle always twice in By means of the sis or in the third stage or step they are not present direct succession, whereby the uniform flow is upset. In View thereof the eficiency of the rotary piston engine is reduced considerably, immaterial whether the same is constructed as pump or as power engine.

Pistons of a considerably improved efficiency are produced according to the present invention (Figs. 6 and 7) in that the width of the individual cuts is less than the width of the ribs. By correspondingly displacing the individual cuts there are produced ribs of alternatingly different widths b and b so that alternating broader and smaller pistons and intermediate slots 0 and e are formed. The cuts are displaced circumferentially always for the same extent at. The chambers through which the operating medium passes in succession are not displaced for the whole width of the chamber and are connected with one another by smaller channel-shaped chambers e, so that the operating medium flows from one chamber 0 into the next chamber smoothly without essentially altering its direction of fiow, whereby shocks, eddies and the like are avoided. When comparing the known method (Fig. 5) with the present method (Fig. 6) it will be readily seen that the same number of ribs or windings are formed over a smaller width Z (Fig. 6) by means of the method according to the'present invention. Thus it is seen that according to the present invention a larger number of ribs or windings are present and therefore larger pressures can be overcome in view of the improved packing. The developed piston-body shown in Fig. '7 differs from the piston-body shown in Fig. 6 in that the displacement of the cuts is gradually increased circumferentially. In order to generate the development shown in Fig. 7, the piston-body is manufactured in the following manner. In the illustrated embodiment altogether fourteen cuts have been made. Thereby are produced three groups of larger chambers c with smaller intermediate chambers e which serve as connecting channels. The broader chambers c are gradually lengthened, while the smaller intermediate chambers e are shortened anymore. Therefore the volume of the individual larger chambers c gradually increases whereby the rotation in an opposite direction produces a compression of the operating medium. The piston-bodies thus formed are preferably suited for use in connection with power engines, compressors, high pressure pumps and the like. of course the circular displacement of the cuts may be varied according to requirement. For instance every cut may be displaced a different distance, for instance a gradually increasing or decreasing distance, with respect to the preceding cut. Instead of producing the piston-windings or ribs by cutting the same out of a hollow cylinder, the

complete piston may be produced by forging the workpiece substantially into the correct shape and subsequently machining it to the correct shape, whereby a large part of the work of fixing the workpiece is dispensed with.

I claim:-

1. Process of making rotary pistons with stepped windings for use in connection with rotary piston engines which consists in cutting in successive steps a cylindric member, the inner diameter of which corresponds to the diameter of the body portion of the piston member, at a right angle with respect to the axis of the cylindric member and down to the inner wall of the latter, the slots thus formed being displaced with respect to one another on the periphery as well as in the axial direction to produce a continuous member forming the piston windings.

2. Process of making rotary pistons with stepped windings for use in connection with rotary piston engines which consists in cutting in successive steps in a single operation cooperating hollow cylindric piston members at a right angle with respect to the axis and down to the inner wall of the latter, and positively rotating said piston members in opposite directions and for the same distance after each cutting step.

3. Process of making rotary pistons with stepped windings for use in connection with rotary piston engines which consists in cutting in successive steps in a single operation cooperating hollow cylindric piston members at a right angle with respect to the axis and down to the inner wall of the latter, and positively rotating said piston members in opposite directions and for the same distance after each cutting step, the width of the individual slots being smaller than the width of the windings of the slotted piston members.

4. Process of making rotary pistons with stepped windings for use in connection with rotary piston engines which consists in slotting in a singleoperation cooperating hollow cylindric piston members at a right angle with respect to the axis and down to the inner wall of the latter, positively rotating said piston members in opposite directions and for the same distance after each slotting operation, and after the slotting operation feeding the cutter in axial direction for a length which differs from the length of the preceding feed.

5. Arrangement for making rotary pistons with stepped windings for use in connection with rotary piston engines comprising parallel gripping devices for securing the workpieces, means connecting two workpieces and rotating the same in opposite direction a certain distance, a tool cutting slots in said workpieces, and means for feed-- ing said tool transversely with respect to the axis of said gripping devices and for adjusting the tool in the axial direction of the workpieces.

6. Arrangement for making rotary pistons with stepped windings for use in connection with rotary piston engines comprising parallel gripping devices for securing the workpieces, means connecting two workpieces and rotating the same in opposite directions, means for adjusting the extent of rotation of said workpieces, a tool cutting slots in said workpieces, and means for feeding said tool transversely with respect to the axis of said gripping devices and for adjusting the tool in the axial direction of the workpieces.

EMANUEL MOCIGEMBA. 

